Chore: delete unused file (#11641)

src/utils/sync.js

-const SYNC_HOOK_PROP = '$v-sync';
-
-/**
- * v-sync directive
- *
- * Usage:
- *  v-sync:component-prop="context prop name"
- *
- * If your want to sync component's prop "visible" to context prop "myVisible", use like this:
- *  v-sync:visible="myVisible"
- */
-export default {
-  bind(el, binding, vnode) {
-    const context = vnode.context;
-    const component = vnode.child;
-    const expression = binding.expression;
-    const prop = binding.arg;
-
-    if (!expression || !prop) {
-      console.warn('v-sync should specify arg & expression, for example: v-sync:visible="myVisible"');
-      return;
-    }
-
-    if (!component || !component.$watch) {
-      console.warn('v-sync is only available on Vue Component');
-      return;
-    }
-
-    const unwatchContext = context.$watch(expression, (val) => {
-      component[prop] = val;
-    });
-
-    const unwatchComponent = component.$watch(prop, (val) => {
-      context[expression] = val;
-    });
-
-    Object.defineProperty(component, SYNC_HOOK_PROP, {
-      value: {
-        unwatchContext,
-        unwatchComponent
-      },
-      enumerable: false
-    });
-  },
-
-  unbind(el, binding, vnode) {
-    const component = vnode.child;
-    if (component && component[SYNC_HOOK_PROP]) {
-      const { unwatchContext, unwatchComponent } = component[SYNC_HOOK_PROP];
-      unwatchContext && unwatchContext();
-      unwatchComponent && unwatchComponent();
-    }
-  }
-};

test/unit/specs/sync.spec.js

-import { createVue, triggerEvent } from '../util';
-import Sync from 'element-ui/src/utils/sync';
-
-const Test = {
-  template: `<div class="sync-test" v-show="visible">
-    <button @click="visible = false">Hide</button>
-    A test component.
-  </div>`,
-  data() {
-    return {
-      visible: true
-    };
-  }
-};
-
-describe('Sync', () => {
-  it('should not throw when use incorrectly', () => {
-    sinon.stub(window.console, 'warn');
-
-    createVue({
-      template: `
-        <test v-sync>
-        </test>
-      `,
-      components: { Test },
-      directives: { Sync },
-      data() {
-        return {
-          myVisible: true
-        };
-      }
-    });
-
-    expect(window.console.warn.callCount).to.equal(1);
-
-    createVue({
-      template: `
-        <test v-sync:visible>
-        </test>
-      `,
-      components: { Test },
-      directives: { Sync },
-      data() {
-        return {
-          myVisible: true
-        };
-      }
-    });
-
-    expect(window.console.warn.callCount).to.equal(2);
-
-    createVue({
-      template: `
-        <test v-sync.visible>
-        </test>
-      `,
-      components: { Test },
-      directives: { Sync },
-      data() {
-        return {
-          myVisible: true
-        };
-      }
-    });
-
-    expect(window.console.warn.callCount).to.equal(3);
-
-    createVue({
-      template: `
-        <div v-sync:visible="myVisible">
-        </div>
-      `,
-      components: { Test },
-      directives: { Sync },
-      data() {
-        return {
-          myVisible: true
-        };
-      }
-    });
-
-    expect(window.console.warn.callCount).to.equal(4);
-
-    window.console.warn.restore();
-  });
-
-  it('context variable should change when inner component variable change', (done) => {
-    const vm = createVue({
-      template: `
-        <test v-sync:visible="myVisible">
-        </test>
-      `,
-      components: { Test },
-      directives: { Sync },
-      data() {
-        return {
-          myVisible: true
-        };
-      }
-    }, true);
-
-    triggerEvent(vm.$el.querySelector('.sync-test button'), 'click', {});
-    setTimeout(() => {
-      expect(vm.myVisible).to.be.false;
-      done();
-    }, 10);
-  });
-
-  it('inner component variable should change when context variable change', (done) => {
-    const vm = createVue({
-      template: `
-        <test ref="test" v-sync:visible="myVisible">
-        </test>
-      `,
-      components: { Test },
-      directives: { Sync },
-      data() {
-        return {
-          myVisible: true
-        };
-      }
-    }, true);
-
-    vm.myVisible = false;
-
-    setTimeout(() => {
-      expect(vm.$refs.test.visible).to.be.false;
-      expect(vm.$refs.test.$el.style.display).to.equal('none');
-      done();
-    }, 10);
-  });
-
-  it('should unwatch expression after destroy', () => {
-    const vm = createVue({
-      template: `
-        <test ref="test" v-sync:visible="myVisible" v-if="createTest">
-        </test>
-      `,
-      components: { Test },
-      directives: { Sync },
-      data() {
-        return {
-          myVisible: true,
-          createTest: false
-        };
-      }
-    });
-
-    const beforeBindCount = vm._watchers.length;
-    vm.createTest = true;
-    const delay = 50;
-    setTimeout(() => {
-      const afterBindCount = vm._watchers.length;
-      expect(afterBindCount).to.be.equal(beforeBindCount + 1);
-
-      vm.createTest = false;
-      setTimeout(() => {
-        const afterDestroyCount = vm._watchers.length;
-        expect(afterDestroyCount).to.be.equal(beforeBindCount);
-      }, delay);
-    }, delay);
-  });
-});